1. Field of the Invention
The present invention relates to a terminal connector used in electrical systems, particularly in audio and video equipment systems. The present invention also relates to a method of fabricating the terminal connector.
2. Description of the Related Art
Referring to FIG. 5, a conventional terminal connector, shown generally at 100xe2x80x2, includes an electrically conductive terminal plate 14 mounted on an insulative circuit board 10. A terminal 15 is secured to insulative circuit board 10 by a screw portion 17 threaded through a screw hole 16 in terminal plate 14. A knob 19, affixed projecting away from terminal 15 enables screwing and unscrewing of screw portion 17 for making electrical connection, as will be explained.
A cylindrical portion 11, surrounding a part of terminal 15 near a first surface of insulative circuit board 10 and helps avoid lead wire shorts and reduces the chance of electrical contact with a person or an object. Knob 19 of terminal 15 also protrudes away from the first surface. Cylindrical portion 11 has at least one lead wire insertion notch 12 in its outer periphery.
A through hole 13 accommodates adjustable screw portion 17 of terminal 15. Screw portion 17 is centered in cylindrical portion 11. Around through hole 13 a plurality of insertion holes 20 permit insertion of one or more press-in lock pieces 21 and a terminal portion 22 of terminal plate 14 into selected insertion holes 20 to fix terminal plate 14 firmly to insulative circuit board 10.
Referring now also to FIG. 6, terminal body 59xe2x80x2 made from electrically conductive material. Terminal body 59xe2x80x2 has a cylindrical plug connection portion 23, suitable for accepting the insertion of a conventional banana tip, a wire end, or other conductor. A collar 18 is pulled down into stabilizing contact with insulative circuit board 10 when screw portion 17 is tightened. The rim of collar 18 is partially removed to form a pair of anti-slip flats 28 for preventing rotation of terminal body 59xe2x80x2 with respect to covering knob 19.
Terminal body 59xe2x80x2 is conventionally formed by cold forging, i.e. compressing a metal material between dies at temperatures not higher than the material""s recrystallization temperature. Through cold forging, conventional cylindrical plug connection portion 23, collar 18, and screw portion 17 are simultaneously formed. Screw portion 17 and flats 28 are not readily formed by cold forging, and are therefore conventionally machined in a subsequent step.
Referring to FIG. 5, knob 19 is generally cylindrical in shape. A fit hole 25, shaped to receive plug connection portion 23, passes through the center of knob 19. A plug insertion opening 26, having a diameter greater than that of fit hole 25, is formed at the top of fit hole 25. A non-circular collar fit-in recess 24 at the bottom of fit hole 25 engages collar 18, including flats 28.
During assembly, plug connection portion 23 of terminal 15 is inserted into fit hole 25 from below. Then, collar 18 is fitted into collar fit-in recess 24. The top of plug connection portion 23 is deformed outward, by swaging or other process, to create a bent portion 27. Thus, terminal body 59 is engaged and integrally fixed in knob 19 by bent portion 27 and collar 18.
When screw portion 17, of terminal 15, is tightened in screw hole 16 in terminal plate 14, a bottom surface of collar 18 and the top surface of terminal plate 14 sandwich a lead wire (not shown) for electric contact. A banana plug (not shown) may be inserted in plug connection portion 23 of terminal 15 for electric connection. More than one lead wire may be captured in this way, and connected to a conductor inserted into plug connection portion 23 and/or terminal portion 22.
Conventional terminal connectors have had several problems, particularly concerning the configuration and the fabrication method of terminal body 59xe2x80x2.
Conventional terminal body 59xe2x80x2, cannot be fabricated in a single step of cold forging. Therefore, removing part of the above-described collar 18 to form flats 28 requires an additional step. This increases manufacturing cost.
Fabrication by cold forging has advantages including, no waste chip production, exact dimensions, and higher product strength. However, since cold forging is a difficult fabrication method, cold forging can be used to fabricate the terminal body 59xe2x80x2 only in limited production facilities. Accordingly, when fabrication by cold forging is employed, is desirable that the entire terminal body 59xe2x80x2 be formed in a single step to limit transportation costs.
Assembly of conventional terminal body 59xe2x80x2, requires collar 18 to be positioned individually in collar fit-in recesses 24. Since collar fit-in recess 24 and corresponding collar 18 with flats 28 both have non-circular shapes, assembly must proceed slowly.
In addition, assembly of conventional terminal body 59xe2x80x2 and knob 19 cannot be carried out by automatic assembly machine because of the additional individual positioning that is required. As a consequence, increased man-hours are required for assembly.
Incorrect assembly positioning may cause deformation of the peripheries of collar fit-in recesses 24 and corresponding insufficient anti-slip function during assembly. Such deformations may result in unacceptably high rejection rates, with consequent cost increases.
As discussed above, the conventional fabrication steps of terminal body 59xe2x80x2 and later assembly with knob 19 require expensive labor and effort thus increasing fabrication costs and increasing anti-slip failures.
It is an object of the present invention to provide a terminal connector providing an anti-slip function.
It is a further object of the present invention to provide a terminal connector with simple construction.
It is a further object of the present invention to provide a method of single-step fabrication for a terminal body.
It is a further object of the present invention to provide a method of assembling a terminal and allowing anti-slip function without pre-positioning the terminal body.
The present invention relates to a forged terminal body and a resin knob assembled without pre-positioning. Anti-slip projections on the terminal body penetrate the knob during assembly to resist torque during connection. The anti-slip projections have asymmetric triangular cross sections with a steeper side of the triangle facing in the tightening direction. In one embodiment of the invention, the anti-slip projections are prismatic projections radially arranged on a collar. In a second embodiment of the invention, the anti-slip projections extend from the collar along a terminal body upon which the resin knob is press fitted.
According to an embodiment of the invention there is provided a terminal connector comprising: a circuit board, a terminal plate attached to the circuit board, a terminal threadable to the terminal plate allowing adjustment relative to the circuit board, the terminal being a terminal body and a knob covering part of the terminal body, the terminal body with a plug connection portion opposite a screw portion, the terminal body also containing a collar and at least one anti-slip projection, the knob having a fit hole and a collar fit-in recess; the plug connection portion in the fit hole and the collar in the collar fit-in recess engaging the anti-slip projection in the knob.
According to an another embodiment of the invention there is provided a terminal connector further comprising: at least one anti-slip projection having an acute profile arranged radially on the collar on the first side of the collar.
According to another embodiment of the invention there is provided a terminal connector further comprising: at least one anti-slip projection having an acute profile arranged radially on the plug connection portion, along a long axis of the plug connection portion, and anti-slip projections arranged on the boarder between the plug connection portion and the first side of the collar.
According to another embodiment of the invention there is provided a terminal connector further comprising: a rim of the plug connection portion opposite the first side of the collar formed in a bent portion to attach to the fit hole.
According to another embodiment of the invention there is provided a method of fabricating a terminal connector, the method comprising the steps of: forming a terminal body, forming a knob containing a plug insertion opening a fit hole and a collar fit-in recess opposite the plug insertion opening, fitting the terminal body into the knob so that at least one anti-slip projection engages with the knob to form a terminal, and engaging the terminal with a terminal plate attached to an insulative circuit board, so as to be adjustable.
According to another embodiment of the present invention there is provided a method of fabricating a terminal connector further comprising: a plug connection portion opposite a end screw portion, a disk-like collar between the plug connection portion and the screw portion, and at least one anti-slip projection on a first side of the collar on the plug-connection-portion side of the collar.
According to the present invention, a terminal connector and a method of fabricating the same are provided in which a terminal body can be fabricated in a single step and the terminal body and a knob can be assembled without positioning, while offering an anti-slip function as well.
The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which like reference numerals designate the same elements.